【LINUX】扩展mysqli与扩展pdo_mysql的方法与区别

一、php7扩展mysqli方法
1.cd /opt/php-7.2/ext/mysqli到PHP目录的ext下的mysqli
2./opt/php/bin/phpize执行编译后的PHP的phpize(注意是编译后的PHP目录后)
3./configure -with-php-config=/opt/php/bin/php-config --with-mysqli=/usr/bin/mysql_config
3.make && make install
4.extension=mysqli添加到php.ini中
5php -m查看是否添加到mysqli的扩展（由于PHP7取消了mysql的扩展，只能用mysqli或者pdo）

[附带]错误解决方法
# [在安装mysqli的时候，出现error: ext/mysqlnd/mysql_float_to_double.h: No such file or directory]
/opt/php-7.2/ext/mysqli
vim mysqli_api.c
修改源码
把第36行的
#include “ext/mysqlnd/mysql_float_to_double.h”
修改为
#include “/opt/php-7.2/ext/mysqlnd/mysql_float_to_double.h”

三PHP扩展pdo_mysql方法
1.安装PDO组件
cd /你的PHP源码安装地址/ext/pdo
phpize
./configure --with-php-config=/编译后的PHP地址/bin/php-configmake & make install
2.安装PDO_MYSQL组件
cd /你的PHP源码安装地址/ext/pdo_mysql
phpize
./configure --with-php-config=/编译后的PHP地址/bin/php-config --with-pdo-mysql=/usr/make & make install （由于我是用yum安装的mysql 所有会提示地址出错，后来看到别人就用--with-pdo-mysql=/usr/安装成功）果然可以。
3.添加pdo_mysql扩展
extension=pdo_mysql.so
phpinfo()查看扩展

四MySQLi和PDO的用法和区别
连接方式
$pdo = new PDO("mysql:host=localhost;dbname=database", 'username', 'password');
$mysqli = mysqli_connect('localhost','username','password','database');

PDO基本操作

$dsn="mysql:dbname=test;host=localhost";
$db_user='root';
$db_pass='admin';
try{
 $pdo=new PDO($dsn,$db_user,$db_pass);
}catch(PDOException $e){
 echo '数据库连接失败'.$e->getMessage();
}
//新增
$sql="insert into buyer (username,password,email) values ('ff','123456','[email protected]')";
$res=$pdo->exec($sql);
echo '影响行数：'.$res;
 
//修改
$sql="update buyer set username='ff123' where id>3";
$res=$pdo->exec($sql);
echo '影响行数：'.$res;
//查询
$sql="select * from buyer";
$res=$pdo->query($sql);
foreach($res as $row){
 echo $row['username'].'
';
}
//删除
$sql="delete from buyer where id>5";
$res=$pdo->exec($sql);
echo '影响行数：'.$res;

mysqli基本操作

 //数据库操作类
 class DBUtil{
  private $host="localhost";
  private $username="root";
  private $password="123456";
  private $dbname="student";
  private $conn;
  public function DBUtil(){
   $this->conn=new mysqli($this->host, $this->username, $this->password,$this->dbname) or die($this->conn->connect_error);
  }
 //查询
  public function query($sql){
   $all= $this->conn->query($sql);
   return $all;
  }
 //插入,修改，删除
  public function otherOperate($sql){
   if($this->conn->query($sql)){
    if($this->conn->affected_rows>0){
      return "OK";
    }else{
      return "ERROOR";
    }
   }
  }
  public function close(){
   $this->conn->close();
  }
 }
?>

mysql数据库基础

 
#显示数据库
show databases;
 
#判断是否存在数据库wpj1105,有的话先删除
drop database if exists wpj1105;
 
#创建数据库
create database wpj1105;
 
#删除数据库
drop database wpj1105;
 
#使用该数据库
use wpj1105;
 
#显示数据库中的表
show tables;
 
#先判断表是否存在,存在先删除
drop table if exists student;
 
#创建表
create table student(
id int auto_increment primary key,
name varchar(50),
sex varchar(20),
date varchar(50),
content varchar(100)
)default charset=utf8;
 
#删除表
drop table student;
 
#查看表的结构
describe student;  #可以简写为desc student;
 
#插入数据
insert into student values(null,'aa','男','1988-10-2','......');
insert into student values(null,'bb','女','1889-03-6','......');
insert into student values(null,'cc','男','1889-08-8','......');
insert into student values(null,'dd','女','1889-12-8','......');
insert into student values(null,'ee','女','1889-09-6','......');
insert into student values(null,'ff','null','1889-09-6','......');
#查询表中的数据
select * from student;
select id,name from student;
 
#修改某一条数据
update student set sex='男' where id=4;
 
#删除数据
delete from student where id=5;
 
# and 且
select * from student where date>'1988-1-2' and date<'1988-12-1';
 
# or 或
select * from student where date<'1988-11-2' or date>'1988-12-1';
  
#between
select * from student where date between '1988-1-2' and '1988-12-1';
 
#in 查询制定集合内的数据
select * from student where id in (1,3,5);
 
#排序 asc 升序  desc 降序
select * from student order by id asc;
 
#分组查询 #聚合函数
select max(id),name,sex from student group by sex;
 
select min(date) from student;
 
select avg(id) as '求平均' from student;
 
select count(*) from student;   #统计表中总数
 
select count(sex) from student;   #统计表中性别总数  若有一条数据中sex为空的话,就不予以统计~
 
select sum(id) from student;
 
#查询第i条以后到第j条的数据(不包括第i条)
select * from student limit 2,5;  #显示3-5条数据